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605 lines
14 KiB
605 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. |
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* Authors: David Chinner and Glauber Costa |
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* |
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* Generic LRU infrastructure |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/mm.h> |
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#include <linux/list_lru.h> |
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#include <linux/slab.h> |
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#include <linux/mutex.h> |
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#include <linux/memcontrol.h> |
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#include "slab.h" |
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#include "internal.h" |
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#ifdef CONFIG_MEMCG_KMEM |
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static LIST_HEAD(memcg_list_lrus); |
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static DEFINE_MUTEX(list_lrus_mutex); |
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static inline bool list_lru_memcg_aware(struct list_lru *lru) |
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{ |
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return lru->memcg_aware; |
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} |
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static void list_lru_register(struct list_lru *lru) |
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{ |
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if (!list_lru_memcg_aware(lru)) |
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return; |
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mutex_lock(&list_lrus_mutex); |
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list_add(&lru->list, &memcg_list_lrus); |
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mutex_unlock(&list_lrus_mutex); |
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} |
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static void list_lru_unregister(struct list_lru *lru) |
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{ |
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if (!list_lru_memcg_aware(lru)) |
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return; |
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mutex_lock(&list_lrus_mutex); |
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list_del(&lru->list); |
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mutex_unlock(&list_lrus_mutex); |
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} |
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static int lru_shrinker_id(struct list_lru *lru) |
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{ |
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return lru->shrinker_id; |
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} |
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static inline struct list_lru_one * |
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list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx) |
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{ |
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if (list_lru_memcg_aware(lru) && idx >= 0) { |
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struct list_lru_memcg *mlru = xa_load(&lru->xa, idx); |
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return mlru ? &mlru->node[nid] : NULL; |
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} |
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return &lru->node[nid].lru; |
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} |
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static inline struct list_lru_one * |
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list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr, |
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struct mem_cgroup **memcg_ptr) |
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{ |
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struct list_lru_node *nlru = &lru->node[nid]; |
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struct list_lru_one *l = &nlru->lru; |
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struct mem_cgroup *memcg = NULL; |
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if (!list_lru_memcg_aware(lru)) |
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goto out; |
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memcg = mem_cgroup_from_obj(ptr); |
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if (!memcg) |
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goto out; |
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l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg)); |
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out: |
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if (memcg_ptr) |
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*memcg_ptr = memcg; |
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return l; |
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} |
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#else |
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static void list_lru_register(struct list_lru *lru) |
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{ |
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} |
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static void list_lru_unregister(struct list_lru *lru) |
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{ |
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} |
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static int lru_shrinker_id(struct list_lru *lru) |
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{ |
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return -1; |
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} |
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static inline bool list_lru_memcg_aware(struct list_lru *lru) |
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{ |
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return false; |
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} |
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static inline struct list_lru_one * |
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list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx) |
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{ |
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return &lru->node[nid].lru; |
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} |
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static inline struct list_lru_one * |
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list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr, |
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struct mem_cgroup **memcg_ptr) |
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{ |
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if (memcg_ptr) |
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*memcg_ptr = NULL; |
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return &lru->node[nid].lru; |
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} |
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#endif /* CONFIG_MEMCG_KMEM */ |
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bool list_lru_add(struct list_lru *lru, struct list_head *item) |
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{ |
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int nid = page_to_nid(virt_to_page(item)); |
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struct list_lru_node *nlru = &lru->node[nid]; |
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struct mem_cgroup *memcg; |
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struct list_lru_one *l; |
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spin_lock(&nlru->lock); |
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if (list_empty(item)) { |
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l = list_lru_from_kmem(lru, nid, item, &memcg); |
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list_add_tail(item, &l->list); |
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/* Set shrinker bit if the first element was added */ |
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if (!l->nr_items++) |
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set_shrinker_bit(memcg, nid, |
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lru_shrinker_id(lru)); |
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nlru->nr_items++; |
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spin_unlock(&nlru->lock); |
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return true; |
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} |
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spin_unlock(&nlru->lock); |
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return false; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_add); |
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bool list_lru_del(struct list_lru *lru, struct list_head *item) |
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{ |
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int nid = page_to_nid(virt_to_page(item)); |
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struct list_lru_node *nlru = &lru->node[nid]; |
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struct list_lru_one *l; |
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spin_lock(&nlru->lock); |
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if (!list_empty(item)) { |
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l = list_lru_from_kmem(lru, nid, item, NULL); |
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list_del_init(item); |
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l->nr_items--; |
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nlru->nr_items--; |
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spin_unlock(&nlru->lock); |
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return true; |
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} |
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spin_unlock(&nlru->lock); |
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return false; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_del); |
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void list_lru_isolate(struct list_lru_one *list, struct list_head *item) |
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{ |
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list_del_init(item); |
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list->nr_items--; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_isolate); |
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void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item, |
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struct list_head *head) |
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{ |
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list_move(item, head); |
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list->nr_items--; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_isolate_move); |
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unsigned long list_lru_count_one(struct list_lru *lru, |
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int nid, struct mem_cgroup *memcg) |
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{ |
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struct list_lru_one *l; |
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long count; |
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rcu_read_lock(); |
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l = list_lru_from_memcg_idx(lru, nid, memcg_kmem_id(memcg)); |
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count = l ? READ_ONCE(l->nr_items) : 0; |
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rcu_read_unlock(); |
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if (unlikely(count < 0)) |
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count = 0; |
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return count; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_count_one); |
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unsigned long list_lru_count_node(struct list_lru *lru, int nid) |
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{ |
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struct list_lru_node *nlru; |
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nlru = &lru->node[nid]; |
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return nlru->nr_items; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_count_node); |
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static unsigned long |
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__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk) |
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{ |
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struct list_lru_node *nlru = &lru->node[nid]; |
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struct list_lru_one *l; |
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struct list_head *item, *n; |
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unsigned long isolated = 0; |
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restart: |
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l = list_lru_from_memcg_idx(lru, nid, memcg_idx); |
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if (!l) |
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goto out; |
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list_for_each_safe(item, n, &l->list) { |
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enum lru_status ret; |
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/* |
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* decrement nr_to_walk first so that we don't livelock if we |
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* get stuck on large numbers of LRU_RETRY items |
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*/ |
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if (!*nr_to_walk) |
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break; |
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--*nr_to_walk; |
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ret = isolate(item, l, &nlru->lock, cb_arg); |
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switch (ret) { |
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case LRU_REMOVED_RETRY: |
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assert_spin_locked(&nlru->lock); |
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fallthrough; |
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case LRU_REMOVED: |
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isolated++; |
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nlru->nr_items--; |
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/* |
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* If the lru lock has been dropped, our list |
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* traversal is now invalid and so we have to |
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* restart from scratch. |
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*/ |
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if (ret == LRU_REMOVED_RETRY) |
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goto restart; |
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break; |
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case LRU_ROTATE: |
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list_move_tail(item, &l->list); |
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break; |
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case LRU_SKIP: |
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break; |
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case LRU_RETRY: |
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/* |
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* The lru lock has been dropped, our list traversal is |
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* now invalid and so we have to restart from scratch. |
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*/ |
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assert_spin_locked(&nlru->lock); |
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goto restart; |
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default: |
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BUG(); |
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} |
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} |
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out: |
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return isolated; |
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} |
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unsigned long |
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list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk) |
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{ |
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struct list_lru_node *nlru = &lru->node[nid]; |
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unsigned long ret; |
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spin_lock(&nlru->lock); |
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ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate, |
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cb_arg, nr_to_walk); |
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spin_unlock(&nlru->lock); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_walk_one); |
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unsigned long |
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list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk) |
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{ |
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struct list_lru_node *nlru = &lru->node[nid]; |
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unsigned long ret; |
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spin_lock_irq(&nlru->lock); |
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ret = __list_lru_walk_one(lru, nid, memcg_kmem_id(memcg), isolate, |
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cb_arg, nr_to_walk); |
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spin_unlock_irq(&nlru->lock); |
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return ret; |
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} |
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unsigned long list_lru_walk_node(struct list_lru *lru, int nid, |
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list_lru_walk_cb isolate, void *cb_arg, |
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unsigned long *nr_to_walk) |
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{ |
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long isolated = 0; |
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isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg, |
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nr_to_walk); |
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#ifdef CONFIG_MEMCG_KMEM |
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if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { |
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struct list_lru_memcg *mlru; |
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unsigned long index; |
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xa_for_each(&lru->xa, index, mlru) { |
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struct list_lru_node *nlru = &lru->node[nid]; |
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spin_lock(&nlru->lock); |
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isolated += __list_lru_walk_one(lru, nid, index, |
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isolate, cb_arg, |
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nr_to_walk); |
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spin_unlock(&nlru->lock); |
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if (*nr_to_walk <= 0) |
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break; |
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} |
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} |
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#endif |
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return isolated; |
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} |
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EXPORT_SYMBOL_GPL(list_lru_walk_node); |
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static void init_one_lru(struct list_lru_one *l) |
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{ |
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INIT_LIST_HEAD(&l->list); |
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l->nr_items = 0; |
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} |
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#ifdef CONFIG_MEMCG_KMEM |
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static struct list_lru_memcg *memcg_init_list_lru_one(gfp_t gfp) |
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{ |
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int nid; |
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struct list_lru_memcg *mlru; |
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mlru = kmalloc(struct_size(mlru, node, nr_node_ids), gfp); |
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if (!mlru) |
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return NULL; |
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for_each_node(nid) |
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init_one_lru(&mlru->node[nid]); |
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return mlru; |
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} |
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static void memcg_list_lru_free(struct list_lru *lru, int src_idx) |
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{ |
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struct list_lru_memcg *mlru = xa_erase_irq(&lru->xa, src_idx); |
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/* |
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* The __list_lru_walk_one() can walk the list of this node. |
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* We need kvfree_rcu() here. And the walking of the list |
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* is under lru->node[nid]->lock, which can serve as a RCU |
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* read-side critical section. |
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*/ |
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if (mlru) |
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kvfree_rcu(mlru, rcu); |
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} |
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static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) |
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{ |
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if (memcg_aware) |
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xa_init_flags(&lru->xa, XA_FLAGS_LOCK_IRQ); |
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lru->memcg_aware = memcg_aware; |
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} |
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static void memcg_destroy_list_lru(struct list_lru *lru) |
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{ |
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XA_STATE(xas, &lru->xa, 0); |
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struct list_lru_memcg *mlru; |
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if (!list_lru_memcg_aware(lru)) |
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return; |
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xas_lock_irq(&xas); |
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xas_for_each(&xas, mlru, ULONG_MAX) { |
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kfree(mlru); |
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xas_store(&xas, NULL); |
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} |
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xas_unlock_irq(&xas); |
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} |
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static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid, |
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int src_idx, struct mem_cgroup *dst_memcg) |
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{ |
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struct list_lru_node *nlru = &lru->node[nid]; |
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int dst_idx = dst_memcg->kmemcg_id; |
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struct list_lru_one *src, *dst; |
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/* |
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* Since list_lru_{add,del} may be called under an IRQ-safe lock, |
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* we have to use IRQ-safe primitives here to avoid deadlock. |
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*/ |
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spin_lock_irq(&nlru->lock); |
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src = list_lru_from_memcg_idx(lru, nid, src_idx); |
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if (!src) |
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goto out; |
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dst = list_lru_from_memcg_idx(lru, nid, dst_idx); |
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list_splice_init(&src->list, &dst->list); |
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if (src->nr_items) { |
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dst->nr_items += src->nr_items; |
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set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru)); |
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src->nr_items = 0; |
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} |
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out: |
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spin_unlock_irq(&nlru->lock); |
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} |
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static void memcg_reparent_list_lru(struct list_lru *lru, |
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int src_idx, struct mem_cgroup *dst_memcg) |
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{ |
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int i; |
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for_each_node(i) |
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memcg_reparent_list_lru_node(lru, i, src_idx, dst_memcg); |
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memcg_list_lru_free(lru, src_idx); |
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} |
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void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent) |
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{ |
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struct cgroup_subsys_state *css; |
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struct list_lru *lru; |
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int src_idx = memcg->kmemcg_id; |
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/* |
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* Change kmemcg_id of this cgroup and all its descendants to the |
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* parent's id, and then move all entries from this cgroup's list_lrus |
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* to ones of the parent. |
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* |
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* After we have finished, all list_lrus corresponding to this cgroup |
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* are guaranteed to remain empty. So we can safely free this cgroup's |
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* list lrus in memcg_list_lru_free(). |
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* |
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* Changing ->kmemcg_id to the parent can prevent memcg_list_lru_alloc() |
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* from allocating list lrus for this cgroup after memcg_list_lru_free() |
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* call. |
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*/ |
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rcu_read_lock(); |
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css_for_each_descendant_pre(css, &memcg->css) { |
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struct mem_cgroup *child; |
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child = mem_cgroup_from_css(css); |
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WRITE_ONCE(child->kmemcg_id, parent->kmemcg_id); |
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} |
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rcu_read_unlock(); |
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mutex_lock(&list_lrus_mutex); |
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list_for_each_entry(lru, &memcg_list_lrus, list) |
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memcg_reparent_list_lru(lru, src_idx, parent); |
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mutex_unlock(&list_lrus_mutex); |
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} |
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static inline bool memcg_list_lru_allocated(struct mem_cgroup *memcg, |
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struct list_lru *lru) |
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{ |
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int idx = memcg->kmemcg_id; |
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return idx < 0 || xa_load(&lru->xa, idx); |
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} |
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int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, |
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gfp_t gfp) |
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{ |
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int i; |
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unsigned long flags; |
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struct list_lru_memcg_table { |
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struct list_lru_memcg *mlru; |
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struct mem_cgroup *memcg; |
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} *table; |
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XA_STATE(xas, &lru->xa, 0); |
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if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru)) |
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return 0; |
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gfp &= GFP_RECLAIM_MASK; |
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table = kmalloc_array(memcg->css.cgroup->level, sizeof(*table), gfp); |
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if (!table) |
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return -ENOMEM; |
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/* |
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* Because the list_lru can be reparented to the parent cgroup's |
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* list_lru, we should make sure that this cgroup and all its |
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* ancestors have allocated list_lru_memcg. |
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*/ |
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for (i = 0; memcg; memcg = parent_mem_cgroup(memcg), i++) { |
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if (memcg_list_lru_allocated(memcg, lru)) |
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break; |
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table[i].memcg = memcg; |
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table[i].mlru = memcg_init_list_lru_one(gfp); |
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if (!table[i].mlru) { |
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while (i--) |
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kfree(table[i].mlru); |
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kfree(table); |
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return -ENOMEM; |
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} |
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} |
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xas_lock_irqsave(&xas, flags); |
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while (i--) { |
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int index = READ_ONCE(table[i].memcg->kmemcg_id); |
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struct list_lru_memcg *mlru = table[i].mlru; |
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xas_set(&xas, index); |
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retry: |
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if (unlikely(index < 0 || xas_error(&xas) || xas_load(&xas))) { |
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kfree(mlru); |
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} else { |
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xas_store(&xas, mlru); |
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if (xas_error(&xas) == -ENOMEM) { |
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xas_unlock_irqrestore(&xas, flags); |
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if (xas_nomem(&xas, gfp)) |
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xas_set_err(&xas, 0); |
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xas_lock_irqsave(&xas, flags); |
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/* |
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* The xas lock has been released, this memcg |
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* can be reparented before us. So reload |
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* memcg id. More details see the comments |
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* in memcg_reparent_list_lrus(). |
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*/ |
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index = READ_ONCE(table[i].memcg->kmemcg_id); |
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if (index < 0) |
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xas_set_err(&xas, 0); |
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else if (!xas_error(&xas) && index != xas.xa_index) |
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xas_set(&xas, index); |
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goto retry; |
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} |
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} |
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} |
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/* xas_nomem() is used to free memory instead of memory allocation. */ |
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if (xas.xa_alloc) |
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xas_nomem(&xas, gfp); |
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xas_unlock_irqrestore(&xas, flags); |
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kfree(table); |
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return xas_error(&xas); |
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} |
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#else |
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static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) |
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{ |
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} |
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|
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static void memcg_destroy_list_lru(struct list_lru *lru) |
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{ |
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} |
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#endif /* CONFIG_MEMCG_KMEM */ |
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|
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int __list_lru_init(struct list_lru *lru, bool memcg_aware, |
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struct lock_class_key *key, struct shrinker *shrinker) |
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{ |
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int i; |
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#ifdef CONFIG_MEMCG_KMEM |
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if (shrinker) |
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lru->shrinker_id = shrinker->id; |
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else |
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lru->shrinker_id = -1; |
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#endif |
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lru->node = kcalloc(nr_node_ids, sizeof(*lru->node), GFP_KERNEL); |
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if (!lru->node) |
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return -ENOMEM; |
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for_each_node(i) { |
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spin_lock_init(&lru->node[i].lock); |
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if (key) |
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lockdep_set_class(&lru->node[i].lock, key); |
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init_one_lru(&lru->node[i].lru); |
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} |
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memcg_init_list_lru(lru, memcg_aware); |
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list_lru_register(lru); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(__list_lru_init); |
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void list_lru_destroy(struct list_lru *lru) |
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{ |
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/* Already destroyed or not yet initialized? */ |
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if (!lru->node) |
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return; |
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list_lru_unregister(lru); |
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memcg_destroy_list_lru(lru); |
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kfree(lru->node); |
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lru->node = NULL; |
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#ifdef CONFIG_MEMCG_KMEM |
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lru->shrinker_id = -1; |
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#endif |
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} |
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EXPORT_SYMBOL_GPL(list_lru_destroy);
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